Golf club head alloy, golf club head, heat treatment method for the golf club head alloy, and method for producing golf club head

ABSTRACT

A golf club head alloy is used to solve the problem of insufficient strength of conventional golf club heads. The golf club head alloy comprises 8-9 wt % of aluminum, 3.5-4.5 wt % of vanadium, ≤2 wt % of molybdenum, with the balance being titanium and inevitable impurities. A golf club head produced from the golf club head alloy and a heat treatment method for the golf club head alloy are also disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

The application claims the benefit of Taiwan application serial No. 110130710, filed Aug. 19, 2021, the subject matter of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a golf club head alloy and, more particularly, to a high-strength golf club head alloy, a golf club head cast from the golf club head alloy, a heat treatment method for the golf club head alloy, and a method for producing the golf club head.

2. Description of the Related Art

Titanium alloys are widely used as casting materials for golf club heads due to excellent strength, corrosion resistance and heat resistance. For example, conventional 811 titanium alloy generally includes about 8 wt % of aluminum, 1 wt % of vanadium, 1 wt % of molybdenum, the rest being titanium and inevitable impurities. Thus, golf club heads produced from the conventional 811 titanium alloy have better strength, providing a proper sense of hitting.

Nowadays, users swing golf clubs with stronger force to seek a better sense of hitting. To solve the problem that the golf club head produced from conventional 811 titanium alloy might have insufficient strength, manufacturers adjust the composition of the conventional 811 titanium alloy by removing molybdenum, forming a 140C titanium alloy including about 7.5 wt % of aluminum, 4.5 wt % of vanadium, 1.2 wt % of chromium, the rest being titanium and inevitable impurities. In comparison with the conventional 811 titanium alloy, a golf club head produced from the 140C titanium alloy has higher strength. However, the golf club head produced from 140C titanium alloy is not widely used, as the formation rate of the golf club head produced from the 140C titanium alloy is extremely low.

Thus, improvement to the conventional golf club head alloys is necessary.

SUMMARY OF THE INVENTION

To solve the above problem, an objective of the present invention is to provide a golf club head alloy, such that a golf club head produced from the golf club head alloy has a higher strength.

Another objective of the present invention is to provide a golf club head alloy that can increase the formation rate of the golf club head.

A further objective of the present invention is to provide a golf club head with a better sense of hitting.

Still another objective of the present invention is to provide a heat treatment method for a golf club head alloy, which can increase the strength of the golf club head produced from the golf club head alloy.

As used herein, the term “a” or “an” for describing the number of the elements and members of the present invention is used for convenience, provides the general meaning of the scope of the present invention, and should be interpreted to include one or at least one. Furthermore, unless explicitly indicated otherwise, the concept of a single component also includes the case of plural components.

A golf club head alloy according to the present invention comprises 8-9 wt % of aluminum, 3.5-4.5 wt % of vanadium, ≤2 wt % of molybdenum, with the balance being titanium and inevitable impurities.

A golf club head according to the present invention is produced from the above golf club head alloy.

A heat treatment method for a golf club head alloy according to the present invention comprises: providing the above golf club head alloy as an alloy base material; heating the alloy base material at 450-750° C. for 0.5-2 hours to carry out an aging treatment; and using a quenching medium to cool the alloy base material for 10-20 minutes after the aging treatment to thereby lower the temperature of the alloy base material after the aging treatment to the room temperature.

Thus, by the above metal composition, the golf club head alloy according to the present invention have stable a phase and β phase to improve the quality of the golf club head. Furthermore, in comparison with 811 titanium alloy and 140C titanium alloy, the golf club head alloy according to the present invention has a higher club head formation rate and better mechanical properties, thereby increasing the yield and providing a better sense of hitting. Furthermore, in the method for producing the golf club head according to the present invention, the club head body by casting from the alloy base material undergoes a heat treatment process (such as an aging treatment and a quenching treatment) to form the golf club head. In comparison with the golf club head produced without the heat treatment process, the mechanical properties of the golf club head cast from the alloy base material treated by the heat treatment process can be improved, thereby increasing the strength of the golf club head.

In an example, the golf club head alloy comprises 8.5 wt % of aluminum. Thus, a higher formation rate is obtained when the golf club head alloy is used to produce a golf club head, and the golf club head has a higher strength.

In an example, the golf club head alloy comprises 4 wt % of vanadium. Thus, a higher formation rate is obtained when the golf club head alloy is used to produce a golf club head, and the golf club head has a higher strength.

In an example, the golf club head alloy comprises 1 wt % of molybdenum. Thus, the golf club head produced from the golf club head alloy has a higher strength while increasing the formation rate of the golf club head.

In an example, the golf club head alloy comprises 1 wt % of tantalum. Thus, the golf club head produced from the golf club head alloy has a higher strength while increasing the formation rate of the golf club head.

In an example, the golf club head has a tensile strength of 150-169 ksi and a yield strength of 138-156 ksi. Thus, the golf club head has better quality.

In an example, the golf club head has a density of 4.401-4.413 g/cm³. Thus, the golf club head has better quality.

In an example, the alloy base material is heated at 580-620° C. for 1 hour during the aging treatment of the alloy base material. Thus, the mechanical properties of the alloy base material can be improved.

In an example, the quenching medium is a neutral gas or an inert gas. Thus, a change in the crystal phase of the alloy base material can be avoided, preventing declination of the mechanical properties of the alloy base material.

The present invention will become clearer in light of the following detailed description of illustrative embodiments of this invention.

DETAILED DESCRIPTION OF THE INVENTION

A golf club head alloy of an embodiment according to the present invention comprises aluminum (Al), vanadium (V), molybdenum (Mo), with the balance being titanium and inevitable impurities. Thus, the golf club head alloy may form a titanium alloy, which can be used as a casting material to form a golf club head having excellent strength.

Specifically, aluminum can stabilize the α phase of the titanium alloy. Addition of aluminum into the golf club head alloy may increase the formation rate of the golf club head produced from the golf club head alloy. However, excessive amount of aluminum causes embrittlement of the golf club head, whereas insufficient amount of aluminum results in a poor formation rate. After adjustment, the golf club head alloy according to the present invention comprises 8-9 wt % of aluminum. In an embodiment, the golf club head alloy comprises 8.5 wt % of aluminum. Thus, a higher formation rate and a higher strength are provided when using the golf club head alloy to produce the golf club head.

Vanadium is an isomorphous element of a β phase stabilizing element. Vanadium has a better solid solubility in β phase. Namely, after vanadium dissolves into the alloy crystal lattice, the crystal lattice can be stably maintained. Thus, vanadium is added into the golf club head to increase the strength of the golf club head. However, excessive amount of vanadium causes reduction of the formation rate of the golf club head, whereas the mechanical strength of the golf club head will be below expectation when the amount of vanadium is insufficient. After adjustment, the golf club head alloy according to the present invention comprises 3.5-4.5 wt % of vanadium. In an embodiment, the golf club head alloy comprises 4 wt % of vanadium. Thus, a higher formation rate and a higher strength are provided when using the golf club head alloy to produce the golf club head.

Molybdenum can stabilize the β phase of the titanium alloy. Addition of molybdenum into the golf club head alloy can increase the strength of the golf club head. Thus, the golf club head alloy according to the present invention comprises 2 wt % of molybdenum. In an embodiment, the golf club head alloy comprises 1 wt % of molybdenum. Thus, the golf club can have a higher strength, and the formation rate of the golf club head can be increased.

The golf club head alloy further comprises tantalum which can stabilize the β phase of the titanium alloy. Thus, addition of molybdenum into the golf club head alloy can increase the strength of the golf club head without reducing the formation rate of the golf club head. Thus, the golf club head alloy comprises ≤1 wt % of molybdenum to provide the golf club head with a higher strength while increasing the formation rate of the golf club head.

Additionally, after adjustment of the composition of the golf club head alloy according to the present invention, similar mechanical properties can still be obtained. In an embodiment, the golf club head alloy according to the present invention is comprised of aluminum, vanadium, molybdenum, tantalum, titanium, and inevitable impurities, wherein the weight percentage of aluminum is about 8-9 wt % of aluminum, the weight percentage of vanadium is about 3.5-4.5 wt %, the weight percentage of molybdenum is about 0.5-2.5 wt %, and the weight percentage of tantalum is about 0.5-1.5 wt %.

Furthermore, during production of the golf club head alloy according to the present invention, metal ingots of the above metal elements or a master alloy containing the above metals can be melted and mixed in a high-temperature furnace or can be melted and mixed in a high-frequency furnace, forming an alloy base material containing metals having the above weight percentages. Thus, the alloy base material can be used to cast a golf club head.

Furthermore, a heat treatment may be carried out on the alloy base material according to the present invention. As an example, the heat treatment is a heat treatment process which includes an aging treatment to increase the temperature and a subsequent quenching treatment to reduce the temperature. Regarding the aging treatment, the alloy base material is heated at 450-750° C. for 0.5-2 hours to carry out an aging treatment. In an embodiment, the golf club head is heated at 580-620° C. for 1 hour during the aging treatment of the alloy base material. Regarding the quenching treatment, a quenching medium is used to cool the alloy base material for 10-20 minutes after the aging treatment to thereby lower the temperature of the alloy base material to the room temperature. The quenching medium may be water, oil, inorganic brine solution, organic brine solution, or a gas. In an embodiment, the quenching medium is a neutral gas (e.g., nitrogen gas) or an inert gas (e.g., helium gas or argon gas). Thus, a change in the crystal phase of the alloy base material can be avoided, preventing declination of the mechanical properties of the alloy base material. Accordingly, when using a club head body formed by casting from the alloy base material, after the aging treatment and the quenching treatment, the mechanical properties of the produced golf club head are enhanced.

To prove the golf club heads produced from the golf club head alloy according to the present invention indeed have excellent strength, tests are conducted on club heads (group 1) produced from the 811 titanium alloy and club heads (group 2) produced from the 140C titanium alloy, club heads produced from an embodiment (group 3) of the golf club head alloy according to the present invention, and club heads produced from another embodiment (group 4) of the golf club head alloy according to the present invention (see Table 1). The mechanical properties of the golf club heads are shown in Table 2.

TABLE 1 composition of golf club head alloy of each group (wt %) of tests group Al V Mo Cr Ta Ti 1 8 1 1 — — balance 2 7.5 4.5 — 1.2 — balance 3 8.5 4 1 — 1 balance 4 8.5 4 2 — — balance

TABLE 2 mechanical properties of club heads of each group group tensile strength (ksi) yield strength (ksi) 1 130-140 110-120 2 140-148 130-137 3 150-163 138-148 4 149-169 136-156

According to the above test results, the tensile strength and the yield strength of the golf club heads (groups 3 and 4) produced from the golf club head alloy according to the present invention are higher than those of the golf club heads produced from the 811 titanium alloy (group 1) and the 140C titanium alloy (group 2). Furthermore, the golf club heads produced from the golf club head alloys (group 3) according to the present invention have a density of 4.401-4.405 g/cm³, and the golf club heads produced from the golf club head alloys (group 4) according to the present invention have a density of 4.409-4.413 g/cm³. This shows that the golf club heads produced from the golf club head alloys according to the present invention have a low density while maintaining a certain strength. Furthermore, the compositions of groups 3 and 4 may be adjusted according to needs to obtain similar mechanical properties.

The alloys of the above four groups are also actually used in casting to test the formation rate of the casting of each group. In brief, during casting of the golf club head, a mold is produced, and a liquid alloy is then poured into a mold cavity of the mold. After the temperature of the liquid alloy drops, the liquid alloy solidifies into a shape identical to the mold cavity, obtaining a casting. During the actual production process, not all castings can completely duplicate the shape of the mold cavity. For example, since the fluidity of the liquid alloy is not good, the castings may be damaged or have cavities. The formation rate of casting can be calculated based on the number of castings having flaws. According to the test result, the formation rate of the golf club heads cast from the 140C titanium alloy (group 2) is only 0-2%. By contrast, the formation rate of the golf club heads cast from the golf club head alloys according to the present invention (groups 3 and 4) is 86%. Thus, in addition to production of the golf club head with excellent strength, the golf club head alloy according to the present invention also increases the formation rate of the golf club head.

TABLE 3 mechanical properties at different aging temperatures Aging Tensile Yield Young's group treatment strength (ksi) strength (ksi) modulus (GPa) 3 none 134-144 114-124  95-115 500° C. 1 hr 140-150 118-128  99-119 600° C. 1 hr 143-158 133-143 103-123 4 none 141-151 120-130  93-113 500° C. 1 hr 145-155 120-130 100-120 600° C. 1 hr 154-164 141-151 108-128

As shown in the above table, tests are conducted on the alloys of groups 3 and 4 in Table 1, and their mechanical properties are compared. There are three test groups in aging treatments: (1) untreated (used as a control group); (2) treated at 500° C. for 1 hour (used as a comparative group); and (3) treated at 600° C. for 1 hour (used as a comparative group). As shown in Table 3, in comparison with the golf club head produced from the alloy base material without aging treatment, the mechanical properties of the golf club head can be improved after the aging treatment. Furthermore, in comparison with the aging treatment at 500° C., the aging treatment at 600° C. for 1 hour can provide the golf club head produced from the golf club head alloy with better mechanism properties.

In view of the foregoing, by the above metal composition, the golf club head alloy according to the present invention can have stable a phase and β phase, such that the golf club head cast from the golf club head alloy can have mechanical properties better than the 811 titanium alloy and the 140C titanium alloy, thereby improving the quality of the golf club head. Furthermore, the golf club head produced from the golf club head alloy according to the present invention has a higher club head formation rate and better mechanical properties, increasing the yield and providing a better sense of hitting.

Furthermore, in the method for producing the golf club head according to the present invention, the club head body by casting from the alloy base material undergoes the aging treatment and the quenching treatment to form the golf club head. In comparison with the golf club head produced without the aging treatment and the quenching treatment, the mechanical properties of the golf club head according to the present invention can be improved, thereby increasing the strength of the golf club head.

Thus since the invention disclosed herein may be embodied in other specific forms without departing from the spirit or general characteristics thereof, some of which forms have been indicated, the embodiments described herein are to be considered in all respects illustrative and not restrictive. The scope of the invention is to be indicated by the appended claims, rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein. 

What is claimed is:
 1. A golf club head alloy comprising 8-9 wt % of aluminum, 3.5-4.5 wt % of vanadium, ≤2 wt % of molybdenum, with the balance being titanium and inevitable impurities.
 2. The golf club head alloy as claimed in claim 1, wherein the golf club head alloy comprises 8.5 wt % of aluminum.
 3. The golf club head alloy as claimed in claim 2, wherein the golf club head alloy comprises 4 wt % of vanadium.
 4. The golf club head alloy as claimed in claim 3, wherein the golf club head alloy comprises 1 wt % of molybdenum.
 5. The golf club head alloy as claimed in claim 1, wherein the golf club head alloy further comprises 1 wt % of tantalum.
 6. A golf club head produced from the golf club head alloy set forth in of claim
 1. 7. The golf club head as claimed in claim 6, wherein the golf club head has a tensile strength of 150-169 ksi and a yield strength of 138-156 ksi.
 8. The golf club head as claimed in claim 7, wherein the golf club head has a density of 4.401-4.413 g/cm³.
 9. A heat treatment method for a golf club head alloy, comprising: providing the golf club head alloy set forth in claim 1 as an alloy base material; heating the alloy base material at 450-750° C. for 0.5-2 hours to carry out an aging treatment; and using a quenching medium to cool the alloy base material for 10-20 minutes after the aging treatment to thereby lower the temperature of the alloy base material after the aging treatment to the room temperature.
 10. The heat treatment method for the golf club head alloy as claimed in claim 9, wherein the alloy base material is heated at 580-620° C. for 1 hour during the aging treatment of the alloy base material.
 11. The heat treatment method for the golf club head alloy as claimed in claim 9, wherein the quenching medium is a neutral gas or an inert gas.
 12. A method for producing a golf club head, comprising: forming a club head body by casting from an alloy base material, wherein the alloy base material includes 8-9 wt % of aluminum, 3.5-4.5 wt % of vanadium, ≤2 wt % of molybdenum, with the balance being titanium and inevitable impurities; heating the club head body at 450-750° C. for 0.5-2 hours to carry out an aging treatment; and using a quenching medium to cool the club head body for 10-20 minutes after the aging treatment to thereby lower the temperature of the club head body after the aging treatment to the room temperature. 